Apparatus for packaging products in vacuum or in a modified atmosphere

ABSTRACT

An apparatus for packaging products in vacuum or in a modified atmosphere, comprising:  
     a first conveyor belt, which is adapted to convey at least one product to be packaged;  
     first transport rollers, which are arranged downstream of the first conveyor belt and are adapted to transport an upper film and a lower film which are separate and are adapted to form a packaging pouch for the at least one product;  
     a first heat-sealing bar, which is arranged downstream of the first transport rollers and is adapted to heat-seal the packaging pouch at its leading and trailing ends;  
     a vacuum generation bell, which has a plurality of second heat-sealing bars which are adapted to heat-seal the longer sides of the pouch for packaging the at least one product, and is further provided with a conveyor belt which is adapted to convey the at least one product through the bell; and  
     a further conveyor belt, which is arranged at the output of the bell.

BACKGROUND OF THE INVENTION

[0001] The present invention relates to an apparatus for packaging products, such as food products and the like, in vacuum or in a modified atmosphere.

[0002] Vacuum-packaging machines are currently known which comprise a vacuum pump arranged so as to be connected to a chamber (vacuum chamber) inside which a preformed pouch open on three sides is arranged; the food product to be sealed is arranged inside the pouch.

[0003] In these conventional machines, therefore, the preformed pouch, with the product inside it, is inserted in the vacuum chamber and vacuum is then produced inside the chamber. Heat-sealing is then performed at the free side of the preformed pouch.

[0004] Such machines entail the need to use preformed pouches and therefore have dimensions which are substantially similar to those of the product. Moreover, they require expensive labor and operating steps which increase the time required to achieve the vacuum packaging of the product.

[0005] Moreover, if packaging occurs in a modified atmosphere, much of the gas is wasted, since the gas is dispersed not only inside the pouch but mostly inside the vacuum chamber.

[0006] Italian patent application No. MI99A0001968 discloses an apparatus and a method which provide an improvement with respect to the above-cited conventional machines.

[0007] The disclosed apparatus entails the use of a nozzle arranged so as to be trapped within presser elements which allow the gas, ejected by the nozzle, to be introduced directly within the package formed by the single-folded film.

[0008] However, the fact of using a pre-folded film (particularly a single-folded one) entails a considerable cost for the entire production process and therefore an additional final cost for the packaged product.

[0009] Moreover, the heat-sealing bars used to heat-seal the sides of the pouch are substantially straight, and this can entail drawbacks at the corners of the pouch.

SUMMARY OF THE INVENTION

[0010] The aim of the present invention is to provide an apparatus for packaging products, such as food products and the like, in vacuum or in a modified atmosphere which allows to use flat sheets which are not pre-folded in order to form a pouch for packaging a product.

[0011] Within this aim, an object of the present invention is to provide an apparatus for packaging products, such as food products and the like, in vacuum or in a modified atmosphere which allows to avoid heat-sealing problems at the corners of the pouch that is formed to package the product.

[0012] Another object of the present invention is to provide an apparatus for packaging products, such as food products and the like, in vacuum or in a modified atmosphere which allows higher productivity than conventional apparatuses.

[0013] Another object of the present invention is to provide a method for packaging products in vacuum or in a modified atmosphere by using the above-cited apparatus.

[0014] Another object of the present invention is to provide an apparatus for packaging products, such as food products and the like, in vacuum or in a modified atmosphere which is highly reliable, relatively simple to manufacture and at competitive costs.

[0015] This aim and these and other objects which will become better apparent hereinafter are achieved by an apparatus for packaging products, such as food products and the like, in vacuum or in a modified atmosphere, characterized in that it comprises:

[0016] a first conveyor belt, which is adapted to convey at least one product to be packaged;

[0017] first transport rollers, which are arranged downstream of said first conveyor belt and are adapted to transport an upper film and a lower film which are separate and are adapted to form a packaging pouch for said at least one product;

[0018] a first heat-sealing bar, which is arranged downstream of said first transport rollers and is adapted to heat-seal said packaging pouch at the leading and trailing ends;

[0019] a vacuum generation bell, which has a plurality of second heat-sealing bars which are adapted to heat-seal the longer sides of the pouch for packaging said at least one product, and is further provided with a conveyor belt which is adapted to convey said at least one product through said bell; and

[0020] a further conveyor belt, which is arranged at the output of said bell.

BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Further characteristics and advantages of the invention will become better apparent from the following detailed description of preferred but not exclusive embodiments of the apparatus according to the invention, illustrated only by way of non-limitative example in the accompanying drawings, wherein:

[0022]FIG. 1 is a top plan view of the apparatus according to the present invention;

[0023]FIG. 2 is a schematic side elevation view of the apparatus according to the invention;

[0024]FIG. 3 is a top plan view of a detail of the apparatus according to the present invention;

[0025]FIG. 4 is a side elevation view of the vacuum forming bell of the apparatus according to the present invention; and

[0026]FIG. 5 is a plan view of an embodiment of the heat-sealing/cutting bar used in the apparatus according to the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0027] With reference to the figures, the apparatus according to the invention, generally designated by the reference numeral 1, comprises a first conveyor belt 2 which is adapted to convey at least one product 3 to be packaged, preferably two products 3 arranged side by side.

[0028] The first conveyor belt 2 conveys the product or products 3 proximate to first rollers 4 which transport an upper film 5 and a lower film 6 which are meant to constitute the two halves of a packaging pouch.

[0029] Downstream of the first rollers 4 in the direction of transport of the films 5 and 6 there is a first heat-sealing bar 7, which is meant to heat-seal the leading end of the pouch formed by the two films 5 and 6.

[0030] Downstream of the first heat-sealing bar 7 there is a second conveyor belt 8, which constitutes a portion of the apparatus which forms a sort of accumulation station before the products 3 pass into a bell 10, in which vacuum is formed and the pouch containing the product 3 and formed by the films 5 and 6 is finally sealed.

[0031] Second rollers 11 are provided downstream of the second conveyor belt 8, directly before the inlet to the bell 10.

[0032] The bell 10 has, as shown for example in FIG. 3, second heat-sealing bars which in this case are not arranged transversely to the product advancement direction, as occurs for the heat-sealing bar 7, but longitudinally, i.e., along the product advancement direction.

[0033] The second heat-sealing bars are chosen equal in number to the sides of the pouch or pouches to be sealed.

[0034] In the embodiment shown in the figures, since there are two products 3 on the conveyor belts, it is necessary to perform three heat-seals of the longer sides of the pouches for packaging the products 3.

[0035] Such longitudinal heat-seals are indeed provided by means of the second heat-sealing bars, which therefore in this case are three and are respectively designated by the reference numerals 12 a, 12 b and 12 c.

[0036] Third transport rollers 14 are arranged downstream of the bell 10 and are meant to transport out of the bell 10 the products 3 (whose pouch is designated by the reference numeral 16 in FIG. 1) and also eliminate waste portions, i.e., the excess parts of the pouch that have to be eliminated after the longitudinal heat-seals performed by the second heat-sealing bars 12 a-12 c.

[0037]FIG. 4 is a front elevation view of the bell 10 of the apparatus according to the invention, illustrating the three heat-sealing bars 12 a, 12 b and 12 c, which are connected to the upper portion of the bell 20 which closes on the lower portion 21 of said bell within which a third conveyor belt 22 slides.

[0038] Finally, a fourth conveyor belt 23 is arranged downstream of the third rollers 14 and allows to convey to the output the packaged product or products and to eliminate the waste produced by the heat-sealing and cutting operations performed simultaneously by the longitudinal heat-sealing bars.

[0039] Again with reference to FIG. 4, it can be seen that there are nozzles 25 which are arranged adjacent to the empty region formed within the bell 10 as a consequence of the closure of the upper portion 20 against the lower portion 21.

[0040] The nozzles are adapted to introduce gas in the bell 10.

[0041] In practice, the operation of the apparatus according to the invention is as follows.

[0042] Initially, the product or products 3 are deposited on the first conveyor belt 2, while the upper film 5 and the lower film 6 are transported by the first rollers 4. The product 3 is then made to advance by the first conveyor belt 2 and is inserted between the two films 5 and 6, which have been heat-sealed beforehand by the first heat-sealing bar 7 at the “leading” side of the package obtained by coupling the films 5 and 6.

[0043] The leading side substantially corresponds to the shorter side of the pouch 16 which is the first to enter the bell 10.

[0044] Then, while the product is inserted between the two films 5 and 6, the heat-sealing bar 7 performs a second heat-seal in order to seal the second shorter side of the pouch 16. At this point, therefore, the product 3 is retained by the two leading and trailing heat-seals performed by the heat-sealing bar 7 and is transported by the second conveyor belt 8, which acts as a sort of accumulation buffer and whose length can be predetermined at will according to the type of product to be packaged.

[0045] At this point, the second rollers 11 transport the product, which is already partially packaged, into the bell 10, where vacuum is produced and gas is injected by means of the nozzles 25.

[0046] The injection of gas is an optional step, and the gas, by way of the arrangement of the nozzles 25, is thus optionally injected only into the pouch 16.

[0047] The pressure in the bell 10 can then be returned to the atmospheric value, since the pouch will not collapse onto the product due to the presence of the gas injected into it.

[0048] The heat-sealing of the longer sides of the pouch 16 is then performed by means of the second heat-sealing bars 12 a-12 c.

[0049] As mentioned, the number of the second heat-sealing bars depends on the number of products conveyed into the bell. In the case shown in the figures, there are three of such heat-sealing bars because the longer sides of the pouches 16 to be sealed are three.

[0050] The heat-sealing bars perform both heat-sealing and simultaneous cutting of the portions of film 5 and 6 which are no longer required as a consequence of the heat-sealing operation.

[0051] The product, now packaged in its pouch 16, is then transported by the fourth conveyor belt 23 in order to be discharged at the output, and at the same time the waste portions of the films 5 and 6 are discarded and transported out of the bell 10. The packaged product must of course be released after opening the bell 10.

[0052]FIGS. 5 and 3 show two different embodiments for the first heat-sealing bar 7.

[0053] In the first embodiment, the heat-sealing bar 7 is shaped so as to have recessed portions 30 with edges which are radiused by means of curved lines, so as to appropriately heat-seal the corners of the pouch 16 without producing dog-ears which are unpleasant for the aesthetic appearance of the packaged product.

[0054] In detail, FIG. 5 instead illustrates a second embodiment of the heat-sealing bar 7 which illustrates that the recessed portions, which in this case are designated by the reference numeral 31, have edges which form a 90° angle and in which the recessed portions 30 substantially have the dimensions of the shorter side of the pouch 16 to be sealed.

[0055]FIG. 5 further illustrates the cutting blade 32 of the first heat-sealing bar 7, which is arranged substantially along the entire contoured perimeter of the heat-sealing bar 7.

[0056] A cutting blade 32 is of course present also in the case of the heat-sealing bar 7 shown in FIG. 3.

[0057] In practice, the apparatus according to the invention allows to use a flat film instead of a pre-folded film (for example single-folded film), whose cost is considerably higher and therefore affects the final cost of the packaged product.

[0058] Moreover, the gas is injected by the nozzles in the bell directly into the pouch, which in this step is heat-sealed at the leading and trailing sides, subsequently allowing to return the pressure in the bell to the atmospheric value, since the gas in the pouch avoids the collapse of said pouch onto the product, with a consequent unpleasant aesthetic effect.

[0059] The collapse of the pouch, for example in the case of packaged meat, would lead to leakage of the blood contained in the meat and accordingly the package would be aesthetically damaged.

[0060] In addition, the first contoured heat-sealing bar allows to perform curved heat-seals at the comers of the pouch 16, thus avoiding the problem of so-called “dog ears” which may form at these corners.

[0061] In practice it has been observed that the apparatus and the method according to the invention fully achieve the intended aim and objects, since they allow to obtain products packaged in a pouch starting from two separate films without having to resort to pre-folded films.

[0062] The apparatus thus conceived is susceptible of numerous modifications and variations, all of which are within the scope of the inventive concept; all the details may further be replaced with other technically equivalent elements.

[0063] In practice, the materials employed, so long as they are compatible with the specific use, as well as the dimensions, may be any according to requirements and to the state of the art.

[0064] The disclosures in Italian Patent Application No. MI2000A000187 from which this application claims priority are incorporated herein by reference. 

What is claimed is:
 1. An apparatus for packaging products in vacuum or in a modified atmosphere, comprising: a first conveyor belt, which is adapted to convey at least one product to be packaged; first transport rollers, which are arranged downstream of said first conveyor belt and are adapted to transport an upper film and a lower film which are separate and are adapted to form a packaging pouch for said at least one product; a first heat-sealing bar, which is arranged downstream of said first transport rollers and is adapted to heat-seal said packaging pouch at the leading and trailing ends; a vacuum generation bell, which has a plurality of second heat-sealing bars which are adapted to heat-seal the longer sides of the pouch for packaging said at least one product, and is further provided with a conveyor belt which is adapted to convey said at least one product through said bell; and a further conveyor belt, which is arranged at the output of said bell.
 2. The apparatus according to claim 1 , comprising an additional conveyor belt which is arranged downstream of said first heat-sealing bar and upstream of said bell.
 3. The apparatus according to claim 2 , wherein said additional conveyor belt arranged between said first heat-sealing bar and said bell is driven by second transport rollers.
 4. The apparatus according to claim 1 , wherein said first heat-sealing bar is contoured, with recesses which are adapted to form leading and trailing heat-seals for said pouch.
 5. The apparatus according to claim 4 , wherein said recesses of said first heat-sealing bar have sharp edges.
 6. The apparatus according to claim 4 , wherein said recesses of said first heat-sealing bar are rounded with curved blending portions.
 7. The apparatus according to claim 1 , wherein said first heat-sealing bar is arranged transversely to an advancement direction of said at least one product to be packaged.
 8. The apparatus according to claim 1 , wherein said second heat-sealing bars are arranged longitudinally along an advancement direction of said at least one product to be packaged.
 9. The apparatus according to claim 1 , wherein third transport rollers are provided at the output of said bell.
 10. The apparatus according to claim 1 , wherein said bell comprises an upper portion which is adapted to couple to a lower portion which is peripherally provided with gas injection nozzles adapted to inject gas into a partially formed pouch that passes through said bell.
 11. A method for packaging products in vacuum or in a modified atmosphere, comprising the steps of: unwinding from respective reels an upper film and a lower film which are adapted to constitute at least one packaging pouch for at least one product; inserting said at least one product between said upper film and said lower film, after heat-sealing a leading side of the pouch to be formed; heat-sealing a trailing side of said pouch and inserting said pouch in a vacuum forming bell; generating a vacuum in said bell and sealing longer sides of said pouch; opening said bell and expelling a packaged product, eliminating the waste of said upper film and of said lower film.
 12. The method according to claim 11 , wherein the steps of heat-sealing the leading and trailing sides of said pouch are provided by means of a first contoured heat-sealing bar.
 13. The method according to claim 11 , further comprising the step of: introducing gas in said pouch, when said pouch is inside said bell.
 14. The method according to claim 13 , comprising the step of returning the pressure in said bell to an atmospheric value after said gas has been injected into said pouch.
 15. The method according to claim 11 , wherein said steps of heat-sealing said leading and trailing sides of said pouch comprise cutting, simultaneously with the heat-sealing operation, excess portions of the upper and lower films.
 16. The method according to claim 11 , wherein said upper film and said lower film are unwound from separate reels and are transported by first transport rollers, said at least one product to be packaged being inserted between said first transport rollers. 